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Re: Evaluating SystemTap for Network Response Times
- From: fche at redhat dot com (Frank Ch. Eigler)
- To: Nathan DeBardeleben <ndebard at lanl dot gov>
- Cc: systemtap at sources dot redhat dot com
- Date: 02 Feb 2006 10:23:53 -0500
- Subject: Re: Evaluating SystemTap for Network Response Times
- References: <20060131182916.GB15048@redhat.com> <43DFB006.8070600@lanl.gov>
Nathan DeBardeleben <ndebard@lanl.gov> writes:
> [...] We probably wouldn't be willing to do anymore static kernel
> instrumentation. [...]
Understood.
> [...] Believe it or not - we find kernel bugs semi-regularly, and
> they can waste tons of our time trying to track them down. [...]
Actually, it's not hard to believe. Back when I worked on a system
that was a heavy user of the kernel (a big database server), one of
its architects mentioned that of all the bugs they found, roughly 25%
were in the OS kernel. I asked what fraction of time was spent in the
kernel, and it also happened to be around 25%. We both then realized
that this might not be a coincidence.
- FChE